Video Assistant Referee causes controversy every week in the Premier League, but how are decisions made, and are they correct?
We take a look at the major incidents, to examine and explain the process both in terms of VAR protocol and the Laws of the Game.
On Tuesday, AFC Bournemouth midfielder David Brooks looked set to be shown a red card against Chelsea when referee Rob Jones was sent to the pitchside monitor to review possible violent conduct on Marc Cucurella.
Was the official correct to reject the VAR's advice, and how common is this in the Premier League?
Chelsea 2-2 Bournemouth
Possible red card: Violent conduct by Brooks on Cucurella
What happened: The game was locked at 1-1 in the 55th minute, with the ball in the hands of Chelsea goalkeeper Robert Sánchez. As he prepared to release it, there was an off-the-ball collision between David Brooks and Marc Cucurella. The VAR, Graham Scott, advised referee Rob Jones that there had been a serious missed incident -- one that hasn't been seen by the officials -- for violent conduct by the Bournemouth player.
VAR decision: Red card rejected, yellow card shown.
VAR review: For the first time in the Premier League, a red-card review was rejected. And it was also the first time that a yellow card was shown when the VAR believed a player should be sent off.
The VAR cannot advise a yellow card ... only a red. But once at the monitor, the referee is in complete control of the final outcome and doesn't have to follow the VAR. Indeed, he could have decided to book Cucurella instead if he wanted.
A VAR is going to make mistakes, because no one is infallible. It's why the monitor exists, to act as a fail-safe against incorrect reviews. But this is the first time it's happened this season, and only the 12th rejection in 5½ seasons of VAR in the English top flight.
For the system to be working totally correctly there shouldn't be any incorrect VAR overturns, as these should get rejected by the referee at the screen.
As we know, however, VAR is far from perfect and referees usually go to the monitor expecting to be proved wrong.
Perhaps because they didn't see Brooks put his arm out to stop Cucurella, the VAR felt it should go to a monitor review. And for the same reason, maybe because Jones was seeing it for the first time he didn't believe he was being shown enough to warrant a red card. While you can question Brooks' action, you can't say there was definitive proof of violent conduct -- be that contact with the head or pulling on Cucurella's hair.
Jones told Brooks he was booking him for a reckless challenge, with the arm going across Cucurella's shoulder, and this was the correct outcome.
If there had been an angle that confirmed Cucurella's hair had been tugged, then Brooks would definitely have seen red -- as Southampton's Jack Stephens did last month for doing exactly that on the same player. Yet you couldn't be certain of it.
It was a strange review, largely because the available replays were of poor quality. Unless you have cameras following every player, there's always the possibility that incidents will happen out of normal shot.
There have been similar situations over the years, where a review has not been advised because the replays aren't good enough. For instance, in December 2023, Aston Villa's Diego Carlos was in a tussle with Eddie Nketiah, with claims that an elbow had been thrown at the Arsenal player, but you really couldn't tell what had happened from the long-distance camera and there was no review.
It's also situation which proves that opposing managers will never agree over contentious incidents.
"They have to explain [it]. If they give a yellow, that means something happened," Chelsea boss Enzo Maresca said after the game.
"I said many times, for me, if there is no intention to take the ball, it's a red. So, how can they judge that it was not dangerous? You cannot judge that it was not dangerous. The intention was just to go against Marc Cucurella. In my opinion, it's a red."
Bournemouth boss Andoni Iraola disagreed: "I've seen nothing violent."
Verdict: Scott, who was fourth official for the Carlos incident described above last season but has exclusively been used as a VAR this season, has a near-perfect record. Across 17 appointments he has no errors to his name. He's had to look at 32 KMIs, returning votes of 159-1 -- only once has a Panel member thought he made a mistake.
But this time, from the available evidence, it simply wasn't possible to say with certainty that Brooks' actions should result in a red card for violent conduct, and the referee was right to reject the review.